1. Field of the Invention
The present invention relates to an automatic article feeding system for successively feeding many kinds of articles into a stocker to temporarily stock them in said stocker and withdrawing and feeding the articles from said stocker to an automatic assembling machine, such as a robot, according to an instruction received from said automatic assembling machine.
More particularly, the present invention relates to an automatic article feeding system which includes means for conveying pallets each of which contains an article or articles such as parts to be assembled and has a mark indicating the kind of the article or articles contained therein, and comprises; means for feeding each of the conveyed pallets into one of the shelves of the stocker according to an empty shelf information supplied by an information processing unit; memory means for storing an address of the shelf in which said pallet has been stocked and further storing information of the kind of the article or articles of said pallet; means for searching the memory means according to the instruction received from the automatic assembling machine to detect existence or non-existence of the article required by the automatic assembling machine and, if in existence, detect the address of the shelf in which the required article is stocked; means for withdrawing the pallet from the stocker according to such detection; means for feeding said pallet to a position for supplying the article contained therein to the automatic assembling machine; means for returning the pallet, after supplying the article to the automatic assembling machine, to the original shelf of the stocker; means for storing the number of the articles retained in the stocker and the existence or non-existence of articles after supplying the article, into the memory means through the information processing unit; display means for displaying the number and the existence or non-existence of articles; and means for discharging an empty pallet, from which all of the articles have been completely supplied to the automatic assembling machine, from the stocker and feeding a new pallet containing an article or articles to the stocker.
2. Description of the Related Art
Recently, rapid advances have been made in automatic assembling techniques and, accordingly, many articles have become manufactured in an automatic assembling system.
With reference to conveying method of products during assembly, the automatic assembling equipment can be classified into a line production system and a non-line production system. The line production system consists of a line for conveying products during assembly and a plurality of automatic assembling machines arranged along said conveying line, as is well known in the art. The line production system is mainly used in production of large quantity and few kinds of articles in which a great number of assembling steps are involved and equipment investment per one kind of article can be greatly increased.
The non-line production system is mainly used, for example, when the quantity of production is small, when the product is not adaptable to a conveyor system, when a relatively small number of assembling steps are involved, or when it is not preferable to greatly increase the equipment investment.
In case of the automatic assembling equipment according to the line production system, which is frequently used in mass-production systems, the speed of conveying products during assembly is high and, consequently, the automatic assembling machines arranged along the assembly line are mainly constructed of high-speed and single-function machines. Furthermore, in case of this equipment, it is general practice to effect assembling operation of one kind of parts at one assembling station and to arrange a device for supplying the parts for assembly at every one of the assembling stations, so that the control of the device for supplying the parts is relatively simple.
On the other hand, in case of the automatic assembling equipment according to the non-line production system, which includes no conveying line for conveying products during assembly or a very short length of such conveying line, if any, the automatic assembling equipment used is frequently constructed of a robot which can effect various kinds of operations. The automatic assembling equipment according to this system has some advantages. That is, many different kinds of products can be assembled by the same equipment if software used to control the robot is changed, depending upon the product to be assembled, and the floor space occupied by the equipment can be decreased, as compared with the line production system. Accordingly, the automatic assembling equipment according to the non-line production system is suitable to production of small quantity and many kinds of articles. In order to adapt this equipment to production of large quantity and many kinds of articles it is necessary to feed many kinds of parts for assembly to one robot, with the result that it is necessary to arrange a great number of feeding apparatus for feeding parts for assembly around said one robot. Accordingly, circumstances surrounding said robot become confused, and the floor space occupied by the equipment and the overall size of the equipment are increased owing to the existence of many feeding apparatus.
Under such circumstances, in case of the automatic assembling machine according to the non-line production system, it is desirable to construct the automatic article feeding device for feeding parts for assembly in a compact size as far as possible and to construct said device in such form that many kinds of parts can be fed by means of the same device. The conventional article feeding device, such as the one heretofore employed to feed the parts for assembly to the automatic assembling machine, is constructed to feed pallets containing an article or articles in the order of the article assembling steps and feed them successively into shelves of a stocker. But, there is substantial difference between the numbers of the articles contained in the respective pallets, depending upon the shape and the size of the article, and the times required for the respective pallets to become empty are different from each other, so that it is impossible to effect the pallet feeding operation in fully automatic manner, without requiring manual operation.